Lithium-ion battery anode including preloaded lithium

ABSTRACT

An energy storage device includes a nano-structured cathode. The cathode includes a conductive substrate, an underframe and an active layer. The underframe includes structures such as nano-filaments and/or aerogel. The active layer optionally includes a catalyst disposed within the active layer, the catalyst being configured to catalyze the dissociation of cathode active material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. non-provisional patent application Ser. No.14/625,372 filed Feb. 18, 2015; which application claims benefit of andpriority to U.S. provisional application Ser. Nos.:

-   -   61/941,205 filed Feb. 18, 2014,    -   61/978,161 filed Apr. 10, 2014, and    -   62/077,221 filed Nov. 8, 2014; and        is a continuation-in-part of U.S. Non-provisional application        Ser. No. 14/176,137 filed Feb. 9, 2014, which in turn claims        priority to provisional patent applications:    -   61/910,955 filed Dec. 2, 2013,    -   61/904,417 filed Nov. 14, 2013,    -   61/887,447 filed Oct. 7, 2013,    -   61/868,002 filed Aug. 20, 2013, and    -   61/806,819 filed Mar. 29, 2013;        and is a continuation in part of U.S. non-provisional        application Ser. No. 13/935,334 filed Jul. 3, 2013 which in turn        is a continuation-in-part of Ser. No. 13/779,409 filed Feb. 27,        2013 which claimed benefit of U.S. provisional application Ser.        Nos. 61/615,179 filed Mar. 23, 2012, 61/752,437 filed Jan. 14,        2013, and which in turn is a continuation in part of Ser. No.        13/725,969 filed Dec. 21, 2012 which in turn claims benefit of        provisional applications:    -   61/677,317 filed Jul. 30, 2012,    -   61/667,876 filed Jul. 3, 2012,    -   61/603,833 filed Feb. 27, 2012, and    -   61/578,545 filed Dec. 21, 2011; and        is a continuation-in-part of U.S. non-provisional application        Ser. No. 13/725,969 filed Dec. 21, 2012, which in turn is a        continuation-in-part of U.S. non-provisional application Ser.        No. 12/904,113 filed Oct. 13, 2010 (issued as U.S. Pat. No.        8,481,214 on Jul. 9, 2013), which in turn claimed benefit of        U.S. provisional application Ser. No. 61/254,090 filed Oct. 22,        2009 and is a continuation-in-part of

-   U.S. non-provisional application Ser. No. 12/392,525 filed Feb. 25,    2009 (issued as U.S. Pat. No. 8,420,258 on Apr. 4, 2013), which in    turn claimed benefit of U.S. provisional application Ser. No.    61/130,679 filed Jun. 2, 2008 and U.S. provisional application Ser.    No. 61/067,018 filed Feb. 25, 2008;    -   this application is a continuation-in-part of U.S. non        provisional application Ser. No. 13/868,957 filed Apr. 23, 2013;        and    -   this application is a continuation-in-part of PCT/US 14/11556        filed Jan. 14, 2014.

The disclosures of the above PCT, provisional and non-provisional patentapplications are hereby incorporated herein by reference.

BACKGROUND Field of the Invention

The invention is in the field of energy storage technology.

Related Art

Energy storage is important in many applications. These include, backuppower, portable electronic devices, and vehicles. One type of energystorage is the lithium ion battery. This battery is currently used invehicles and portable electronics. There is, however, a need forimproved energy storage capacity.

For example, prior art cathodes used in lithium ion batteries sufferfrom low energy density (i.e. lithium cobalt oxide ˜180 mAh/g) whencompared to the best available anode materials (silicon—4000 mAh/g). Toalleviate this issue, there has been focus on developing lithium-airbatteries, at the expense of additional complexity of new separators andchemistries to support the battery coming in contact with air. One ofthe developments is to rely upon the reversible formation/decompositionreaction of Li₂O₂ at the cathode upon cycling. [e.g., “A Reversible andHigher-Rate Li—O₂ Battery”, Science, vol. 337, pgs 563-566]. One issuewith the technique described in this paper is that the materials used tocatalyze the reaction (gold), has a weight that creates an effectiveenergy density of ˜300 mAh/g. The technology also suffers from poorcharging rates. The charging rates being dependent at least in part oncatalyst surface area.

SUMMARY

Various embodiments of invention disclosed herein include new types ofcathodes. These cathodes are optionally used in lithium ion batteries.For example, some embodiments can be used in sealed or un-sealedLithium-air batteries. These embodiments solve problems with the priorart by provided greater energy storage density per unit mass and perunit volume.

Some embodiments of the invention include an energy storage systemcomprising an electrode disposed in a first region of electrolyte andincluding a substrate, a plurality of support filaments attached to thesubstrate, and an ion absorbing material attached to the supportfilaments and configured to expand in volume at least 5 percent whenabsorbing ions; a separator configured to separate the first region anda second region of electrolyte; and a cathode disposed in the secondregion of electrolyte, the cathode, anode and separator configured tooperate as a rechargeable battery.

Some embodiments of the invention include a battery comprising a firstcathode electrode comprising a supporting underframe, an active materialconfigured to release oxygen and lithium from the active material in areduction reaction, the reduction reaction including the reduction of alithium compound, the active material being disposed on the underframe,and an active catalyzer deposited within the active material, thecatalyzer configured to catalyze the reduction reaction; and an anodeelectrode.

Some embodiments of the invention include battery comprising an anode; acathode including a conductive substrate, an underframe attached to thesubstrate, and a catalyst coated on the underframe, the catalyst beingconfigured to catalyze the dissociation of cathode active material; andan electrolyte including the cathode active material.

Some embodiments of the invention include battery comprising: an anode;a cathode including a conductive substrate, an underframe, a catalystcoated on the underframe, the catalyst being configured to catalyze thedissociation of cathode active material, and a binder configured to holdthe underframe in proximity to the substrate; and an electrolyteincluding the cathode active material.

Some embodiments of the invention include battery comprising an anode; acathode including a conductive substrate, an underframe including anaerogel, and a catalyst disposed within the aerogel, the catalyst beingconfigured to catalyze the dissociation of cathode active material; andan electrolyte including the cathode active material.

Some embodiments of the invention include method of making a battery,the method comprising providing an anode; producing a cathode by growingan underframe including a plurality of nanofibers on a conductivesubstrate, and depositing a catalyst on the nanofibers, the catalystbeing configured to catalyze dissociation of cathode active material;and adding an electrolyte between the anode and the cathode, theelectrolyte including the cathode active material.

Some embodiments of the invention include method of making a battery,the method comprising providing an anode; producing a cathode byproviding an underframe including plurality of nanofibers, depositing acatalyst on the nanofibers, the catalyst being configured to catalyzedissociation of cathode active material, and applying the nanofibers toa conductive substrate using a binder; and adding an electrolyte betweenthe anode and the cathode, the electrolyte including the cathode activematerial.

Some embodiments of the invention include a method of making a battery,the method comprising providing an anode; producing a cathode byproviding an underframe including an aerogel, depositing a catalystwithin the aerogel, the catalyst being configured to catalyzedissociation of cathode active material, and applying the aerogel to aconductive substrate; and adding an electrolyte between the anode andthe cathode, the electrolyte including the cathode active material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a cross section of a single element of an energystorage electrode, according to various embodiments of the invention.

FIG. 1B is a cross section illustrating details of a seed layer of FIG.1A according to various embodiments of the invention.

FIG. 1C is a cross section of a portion of the energy storage electrodeof FIG. 1A illustrating an underlayer between an underframe and activelayer, and an over-layer that optionally encapsulates the active layer,according to various embodiments of the invention.

FIG. 2A illustrates an underframe including a vertically aligned arrayof nanotubes or nanowires, according to various embodiments of theinvention.

FIG. 2B illustrates an underframe including a vertically aligned arrayof nanotubes or nanowires, including diameter variation along the lengthof the nanotubes or nanowires, according to various embodiments of theinvention.

FIG. 2C illustrates an underframe including a vertically aligned arrayof nanofibers, with ‘graphitic’ edges exposed, according to variousembodiments of the invention.

FIG. 2D illustrates an underframe including a vertically aligned arrayof branched nanotubes, branched nanofibers, or branched nanowires,according to various embodiments of the invention.

FIG. 2E illustrates an underframe including a template formed aerogel,according to various embodiments of the invention.

FIG. 3 illustrates further details of a cross section of a portion ofthe energy storage electrode of FIG. 1A, according to variousembodiments of the invention.

FIG. 4A illustrates a cross section of several elements of an energystorage electrode with stacked-cup nanofibers, according to variousembodiments of the invention.

FIG. 4B illustrates a cross section of several elements of a stacked-cupnanofiber with exposed ‘graphitic’ edges, according to variousembodiments of the invention.

FIG. 5A illustrates a cross section of several elements of an energystorage electrode including a template formed aerogel, according tovarious embodiments of the invention.

FIG. 5B illustrates a cross section of an aerogel, according to variousembodiments of the invention.

FIG. 6 illustrates a cross section of a prior art rechargeable battery.

FIG. 7 illustrates methods of producing an electrode, according tovarious embodiments of the invention.

DETAILED DESCRIPTION

Various embodiments of the invention include a rechargeable (secondary)battery including an improved electrode. The electrode of the inventionis optionally included within a part of a cathode and/or an anode of asecondary battery/cell 100 to create an improved battery. The electrodetypically includes an electrode extension grown on or attached to asubstrate using a seed layer. The electrode extension is configured toincrease the surface area of the electrode and includes a supportfilament and an intercalation layer. In various embodiments, the supportfilament material includes a carbon nano-tube (CNT), a carbon nano-fiber(CNF), a nano-wire NW (a wire having a diameter less than approximatelyfive micrometer), metal, semiconductor, insulator, silicon, and/or thelike. The CNT, CNF, and/or NW may be single walled or multi walled. Thesupport filament may provide an electrical path to the substrate and amechanical base for the intercalation layer. The intercalation layerprovides a region for absorption and/or donation of ions from theelectrolyte. As used herein, an intercalation layer can be used at bothan anode and a cathode. In various embodiments, the intercalation layerincludes a donor/acceptor material (DAM) configured for donating and/oraccepting the ions from the electrolyte. This ion donating and/oraccepting may include both adsorbing and absorbing processes. Theintercalation layer may expand in volume by at least 5, 10, 15, 50, 100,200 or 400 percent on the absorption of ions.

In various embodiments, the DAM includes silicon, graphite, Sn, Sn—C,inter-metallics, phosphides, nitrides, 3D metal oxides, or LiCoPO4,LiMnPO4, LiMn2O4, LiCoO2, LiNiO2, MnO2, vanadium oxides V2O5 and LiV3O8,polyanionic materials such as Li(1-x)VOPO4, Li(x)FePO4), LiMnO2,Li2FePO4F, doped LiMn2O4, and/or the like. The DAM is deposited or grownon the support filament. In some embodiments, the support filament isprovided with additional strength (e.g., tensile, compression, shear,and/or the like) for supporting the DAM particularly during expansionand/or contraction of the DAM in the intercalation layer. In someembodiments, the DAM covers part but not all of the support filament.For example, portion of the support filament may remain uncoated. Theuncoated portion can provide for flexibility and freedom of movement,for example between the electrode extension and the substrate. In somecircumstances this reduces the likelihood of separation of the supportfilament from the seed layer during expansion and/or contraction of theDAM in the intercalation layer.

The electrode extension increase intercalation volume and surface area,thereby improving energy density of the electrode over a layer ofmaterial deposited on a flat surface. The electrode extensions may serveas a flexible interface between the substrate and intercalation layer,thereby allowing a large degree of expansion in volume (e.g., 2×, 4×,6×, etc.) of the intercalation layer, while at the same time reducing arisk of the material separating from the substrate. The electrodeextension can also reduce diffusion distances of the ions in the bulk ofthe intercalation material, therefore improving power density of theelectrode.

FIG. 1A illustrates a cross section of a single element of an energystorage electrode 100, according to various embodiments of theinvention. One or more of electrode 100 may be used in a rechargeablebattery, such as the rechargeable (secondary) battery of FIG. 6, inaccordance with various embodiments of the invention. The electrode 100includes a substrate 110, an optional seed layer 115, and an energystorage system 190. The energy storage system 190 includes an underframe130 and an active layer 150 (intercalation layer). The seed layer 115may be used to initiate growth of the underframe 130 and may be used tofacilitate connection of the energy storage system 190 to the substrate110. In alternative embodiments the energy storage system 190 is coupleddirectly to the substrate 110. The underframe 110 supports the activelayer 150, as well as the optional overlayer 154 and optional underlayer152. The underframe 130 provides enhanced surface area per unit volumefor uptake and/or deposition of additional materials.

The substrate 110 can comprise graphite coated aluminum, graphite, Ni,Ag, Fe, Mg, Pb, W, Al, Hf, Mo, Pd, Ta, Au, In, Nb, Ti, Zr, Cu, Li, Ni,V, Zn, C, carbides of the above elements, silicides of the aboveelements, oxides of the above elements, nitrides of the above elements,an oxygen permeable membrane, and/or any combination thereof. Note thatthe substrate can include one material, or a combination of more thanone material. (The “above elements” refers to those discussed in thisparagraph.) For instance, the substrate 110 can be composed of bothaluminum and an oxygen permeable membrane. Additionally, the thicknessof the substrate can range in thickness from approximately 5 microns toapproximately 250 microns, 250 microns to 750 microns, 750 microns to 2mm, and 2 mm to 5 mm, or any combination thereof, depending on theparticular application of the secondary battery/cell 100.

In various embodiments, the substrate 110 includes an oxygen permeablemembrane, polymers, porous materials such as aerogel, metal, asemiconductor, and/or an insulator. The substrate 110 may be fabricatedin a variety of shapes. For example, the substrate 110 may be planar(single sided and double sided), cylindrical, finned, and/or the like.In some embodiments, the shape of substrate 110 is selected so as tomaximize available surface area. Finally, the electrode 100 typicallyincludes multiple energy storage systems 190, optionally in an array.

The optional seed layer 115 serves one or more of a number of functionsand may include several sub-layers. For example, the seed layer 115 maycomprise an initial layer 117, an intermediate layer 118, and/or a finallayer 119. The seed layer 115 may be configured to control the crosssectional area (e.g., diameter) of the underframe 130 by controlling anarea in which initial growth of the underframe 130 occurs. The relativeand/or absolute thicknesses of the initial layer 117, an intermediatelayer 118, and/or a final layer 119 can be selected to control the areaof initial growth of the underframe 130 and thus the underframe crosssectional area (e.g., diameter) shown in FIGS. 2A, 2B, 2C, 2D, & 2E).Those skilled in the art of nanotube, nanofiber, nanowire, and aerogelgrowth will appreciate that other methods are also available to controlthe cross sectional area of the underframe 130. In some embodiments, theseed layer 115 may control adhesion of the underframe 130 to thesubstrate 110. The spacing between adjacent underframe 130 and/or thecross section of the underframe 130 may limit the possible thickness ofthe active layer 150, over-layer 154, underlayer 152, and vice-versa.

The seed layer 115 may control a density of initiation points and/or anareal density of growth initiation points for the underframe 130. Thedensity of initiation points determines the density of underframe 130attachment points. The density of attachment points may by between10³/cm² to 10¹¹/cm², generally 10⁷/cm² to 10¹⁰/cm². The initiationdensity may be expressed as a number of support filament initiationsites per unit area, e.g., number/cm². The areal density is the densityof underframe 130 tips that are distal from seed layer 115 and substrate110. The areal density can be greater than the density of attachmentpoints because the underframe 130 may be branched, as discussed furtherelsewhere herein. The areal density may be expressed as a number ofsupport filament tips per unit area, e.g., number/cm².

In some embodiments, the seed layer 115 is a single material depositedon the substrate 110 in a single layer. Alternatively, the seed layer115 includes multiple (2, 3 or more) sub-layers of differing materials,e.g., initial layer 117, intermediate layer 118, and/or final layer 119.Each of the sub-layers of the seed layer 115 may be configured toperform various functions. For example, one of the sub-layers mayinclude a barrier layer configured to prevent migration of atoms betweenlayers; include an adhesion layer configured to bind two layerstogether; a protection layer configured to protect underlying oroverlying layers from chemical/physical degradation; a conduction layerconfigured to provide conductivity; a stress/strain layer configured toact as a mechanical buffer between two layers; a binding/release layerconfigured to bind/release the final seed material to/from theunderlying substrate; a layer configured to inhibit the growth ofnanotube, nanofiber, nanowire, and/or aerogels, and/or a seed layer toinitiate nanotube, nanofiber, nanowire, and/or aerogel growth. Personshaving ordinary skill in the art of thin film growth and deposition willrecognize that there are other utilities a thin film layered structureof seed layer 115 can serve.

FIG. 1B is a cross section illustrating details of the seed layer 115 ofFIG. 1A, according to various embodiments of the invention. The seedlayer 115 illustrated in FIG. 1B includes a stack of sub-layerscomprising different materials. As described elsewhere herein, thesub-layers include, for example, an initial layer 117, an intermediatelayer 118 and a final layer 119. The initial layer 117 is coupled to thesubstrate and forms a base for the intermediate layer 118. Theintermediate layer 118 is deposited on the initial layer 117 andconfigured to form a base for the final layer 119. The final layer 119is deposited on the intermediate layer 118 and is configured to providesites for attachment and initiation of growth of the underframe 130.Alternatively, the final layer 119 is configured to inhibit the growthof a nanotube, nanofiber, nanowire, and/or aerogel.

In various embodiments, the final layer 119 includes molybdenum, iron,cobalt, nickel, carbon, graphite, graphene, and/or the like. Variousmaterials in the final layer 119 may initiate or inhibit growth and/orprovide for attachment of the including nanotube, nanofiber, nanowire,and/or aerogel. The intermediate layer 118 may comprise, for example,iron, cobalt, nickel, titanium, titanium nitride, aluminum, and/or thelike. The initial layer 117 may include, for example, platinum,tungsten, titanium, chromium, and/or the like. It will be appreciatedthat alternative materials may be included in the sub-layers of seedlayer 115.

In various embodiments, the underframe 130 includes nanotube, nanofiber,nanowire, and/or aerogel. More specifically, the nanotube, nanofiber,nanowire, and/or aerogel may comprise materials of metals, carbon,graphene, boron nitride, silicon, TiO₂, copper, transition metals,oxides, nitrides, silicides, carbides, SiO₂, silica, transition metaloxides, TiN, SiC, TiC, and/or any combination thereof. The nanotubes,nanofibers, nanowires, and/or aerogel may be doped with materials,including, but not limited to boron, phosphor, and/or nitrogen. In someembodiments the underframe 130 includes carbon nanotubes or fibershaving a stacked-cup structure. In alternative embodiments, underframe130 is in the form of a mesh and each of energy storage system 190 neednot be attached to substrate 110 and/or seed layer 115 by an end. Thestacked-cup structure provides variable surface texture of theunderframe 130. This surface variation can result in useful variationand/or structure in any of the layers placed on the underframe 130.

The underframe 130 provides a mechanical base for deposition and growthof the active layer 150, underlayer 152, and overlayer 154. Theunderframe 130 may also provide strength (e.g., tensile strength,compression strength, shear strength, and/or the like) to the activelayer 150. The additional strength reduces or prevents damage to theenergy storage system 190 during expansion and/or contraction of theactive layer 150. The nanotubes may include a single wall or multiplewalls. The nanofibers may include a cup like stacking structure alongit's length; the edges of these cups may be described as being‘graphitic’ with respect to their material properties i.e. the edges actas graphene sheets. In some embodiments, the nanotube, nanofiber,nanowire, and/or aerogel of the underframe 130 is configured to act asan active material in which material is adsorbed and/or reactionscatalyzed. In some embodiments, the nanotube, nanofiber, nanowire,and/or aerogel of the underframe 130 is configured to allow for uptakeof additional material, such as gases (O₂, CO₂, CO, N₂, NO₂, NO, H2,etc.), nano-particles and/or thin films, such as gold, platinum,MnO_(x), CuFe, beta-MnO₂/Pt, Pd, Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂,FeO₄, CoFe₂O₄, TiN, TiC, TiO₂, graphite, Ni, Ag, Fe, Mg, Pb, W, Al, Hf,Mo, Pd, Ta, Au, In, Nb, Ti, Zr, Cu, Li, Ni, V, Zn, C, carbides of theabove elements or compounds, silicides of the above elements orcompounds, oxides of the above elements or compounds, nitrides of theabove elements or compounds, and/or any combination thereof. (The “aboveelements or compounds” refers to those elements discussed in thisparagraph.)

In some embodiments, the active layer 150 does coat some but not all ofthe length of the underframe 130. As a result, a portion of theunderframe 130 forms an uncoated region 135. The uncoated region 135 isconfigured to provide a region for flex and motion of the underframe130. This flex can reduce mechanical stress resulting from expansion andcontraction of the active layer 150. If not reduced, this stress cancause breakage and/or separation of the underframe 130 from the seedlayer 115. Additionally, this uncoated region 135 may provide additionalvolume for gas, e.g., O₂, capture and/or sequestration.

The length of the uncoated region 135 may range from several angstromsto several microns. In some embodiments the length of the uncoatedregion 135 is selected such that the active layer 150 does not reach oronly just reaches the seed layer 115. In various embodiments the lengthof the uncoated region 135 is at least 0.1, 0.25, 0.3, 0.5, or 1.0micrometers. In some embodiments, the length of the uncoated region 135is substantially greater than a micron. In various embodiments thelength of the uncoated region 135 is at least 20%, 30%, 40%, 55%, 70%,85%, 90%, or 95% of the total length of the underframe 130 height. Theuncoated region 135 is typically located proximate to the end ofunderframe 130 closest to the seed layer 115. However, uncoated region135 may be provided at other or alternative parts of underframe 130. Forexample, uncoated region 135 may be provided proximate to brancheswithin underframe 130.

In some embodiments, uncoated region 135 is a region that has reducedcoating of active layer 150 relative to other parts of energy storagesystem 190, rather than a region having no coat at all. For example,uncoated region 135 may have a coating of active layer 150 whosethickness is less than 10, 25 or 50% of the thickness of the activelayer 150 found in other regions of energy storage system 190.

FIG. 1C is a cross section of a portion of the energy storage system 190of FIG. 1A, according to various embodiments. An exemplary location ofthis cross section is shown by label “A” in FIG. 1A. In theseembodiments, energy storage system 190 includes an optional underlayer152 between the underframe 130 and the active layer 150, and an optionaloverlayer 154. Overlayer 154 optionally encapsulates the active layer150, forming a barrier between active layer 150 and an electrolyte. Theelectrolyte includes an active material configured to react in anelectrochemical reaction at the cathode (a cathode active material). Thecathode active material may include, for example, lithium ion or someother cation.

In some embodiments, the underlayer 152 is configured to provide a seedlayer for vapor-liquid-solid (VLS) growth of the active layer 150.Alternatively, the underlayer 152 includes a thin layer (e.g., less thanone micrometer) of a metal or a series of metals (e.g., a transitionmetal, gold, silver, copper, nickel, and/or the like) or a salt (e.g.,LiF). Underlayer 152 optionally includes a silicide. Other materials maybe used to form an underlayer 152 depending on the desired effect. Forinstance, the underlayer 152 can be composed of a thin film orparticulate layer with thicknesses that ranges from about 1 nm to 5 nm,3 nm to 7 nm, 5 nm to 12 nm, 10 nm to 17 nm, 13 nm to 25 nm, 20 nm to 47nm, 29 nm to 53 nm, 37 nm to 71 nm, 57 nm to 101 nm, or any combinationthereof. This thin film or particulate layer may have a materialcomposition comprising gold, platinum, MnO_(x), CuFe, beta-MnO₂/Pt, Pd,Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄, CoFe₂O₄, TiN, TiC, TiO₂,and/or any combination thereof. Additionally, underlayer 152 can becomprised of nanoparticles with average diameters of 1 nm, 3 nm, 5 nm, 8nm, 13 nm, 17 nm, 23 nm, 29 nm, 37 nm, 43 nm, 53 nm, 61 nm, 67 nm, 79nm, 97 nm, 115 nm, possibly larger, or any range there between.Underlayer 152 is optionally comprised of both thin films andnanoparticles. Underlayer 152 can also be partially comprised of gelelectrolyes, such as P(VDF-HFP)-based polymer electrolytes, poly acrylicacid, and polyfluorene-based conducting polymers, incorporating acarbon-oxygen functional group (carbonyl). In this case the thickness ofthe underlayer 152 can be as much as 500 nm, 750 nm, 900 nm, 1200 nm, orpossibly more.

The overlayer 154 may be grown and/or deposited on the active layer 150.The over-layer 154 may partially or fully encapsulate the active layer150. The materials that comprise the over-layer 154 include, forexample, metals such as gold, silver, copper, and/or the like. Theover-layer 154 can also include a diamond-like coating (DLC), or aninsulator, such as SiO₂, a binder, a polymer, and/or the like. Thethickness of the over-layer 154 is typically less than one micrometer inthe case of metals, semiconductors or insulators. In variousembodiments, the thickness of the over-layer 154 may be larger than amicrometer for a binder or larger for polymers. For instance, theover-layer 154 can be composed of a thin film with thicknesses thatrange from about 1 nm to 5 nm, 3 nm to 7 nm, 5 nm to 12 nm, 10 nm to 17nm, 13 nm to 25 nm, 20 nm to 47 nm, 29 nm to 53 nm, 37 nm to 71 nm, 57nm to 101 nm, or an combination thereof. This thin film may have amaterial composition comprising of gold, platinum, MnO_(x), CuFe,beta-MnO₂/Pt, Pd, Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄, CoFe₂O₄,TiN, TiC, TiO₂, and/or any combination thereof. Additionally oralternatively, overlayer 154 can be comprised of nanoparticles withaverage diameters of up to 1 nm, 3 nm, 5 nm, 8 nm, 13 nm, 17 nm, 23 nm,29 nm, 37 nm, 43 nm, 53 nm, 61 nm, 67 nm, 79 nm, 97 nm, 115 nm, possiblylarger, or any range there between. These particles may have a materialcomposition comprising gold, platinum, MnO_(x), CuFe, beta-MnO₂/Pt, Pd,Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄, CoFe₂O₄, TiN, TiC, TiO₂,and/or any combination thereof. Overlayer 154 is optionally comprised ofboth thin films and nanoparticles. Overlayer 154 can also be partiallycomprised of gel electrolyes, such as P(VDF-HFP)-based polymerelectrolytes, poly acrylic acid, and polyfluorene-based conductingpolymers, incorporating a carbon-oxygen functional group (carbonyl). Inthis case the thickness of the overlayer 154 can be up to 500 nm, 750nm, 900 nm, 1200 nm, or possibly more.

The active layer 150 may be grown/deposited on the underframe 130 usinga various methods. These methods include, for example, evaporation,sputtering, PECVD (Plasma-Enhanced Chemical Vapor Deposition),low-pressure chemical vapor deposition (LPCVD), VLS (Vapor Liquid Solidsynthesis), electroplating, electro-less deposition, “field-free”chemical vapor deposition (CVD), metal-organic CVD, molecular beamepitaxy (MBE), and/or the like. In some embodiments, the active layer150 distribution over the surface of the underframe 130 is uniform.Alternatively, the active layer 150 thickness is not uniform over thelength of the underframe 130. For example, the uncoated region 135height may vary from 0% to 99% of the height of the underframe 130. Insome embodiments, the active layer 150 proximate to the substrate 110has a smaller thickness relative to the distal end of the underframe130. As such, the thickness of the active layer 150 may increase, alongunderframe 130, with distance from the substrate 110.

The active layer 150 is optionally comprised of Li₂O₂, Li₂O, lithiatedTiS₂, LiOH*H₂O, LiOH, (LiMO₂, M=Mn, Ni, Co), LiFePO₄, lithiated TiO₂,and/or any combination thereof. In various embodiments, the thickness ofthe active layer is from 1-10 nm, 5-50 nm, 15-75 nm, 25-100 nm, 50-200nm, 80-350 nm, 120-600 nm, 175-950 nm, 250-1500 nm, 425-2500 nm,725-4000 mn, any combination thereof, or possibly larger. Nanoparticlesare optionally interspersed within the active layer 150. Thesenanoparticles are comprised of, for example, gold, platinum, MnO_(x),CuFe, beta-MnO₂/Pt, Pd, Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄,CoFe₂O₄, TiN, TiC, TiO₂, or any combination thereof. These nanoparticlesmay have diameters between 1 nm, 3 nm, 5 nm, 8 nm, 13 nm, 17 nm, 23 nm,29 nm, 37 nm, 43 nm, 53 nm, 61 nm, 67 nm, 79 nm, 97 nm, 115 nm, possiblylarger, or any combination thereof. Additionally, the active layer 150may be partially comprised of gel electrolyes, such as P(VDF-HFP)-basedpolymer electrolytes, poly acrylic acid, and polyfluorene-basedconducting polymers, incorporating a carbon-oxygen functional group(carbonyl).

A number of methods may be employed to achieve a desired length for theuncoated region 135. Examples of such methods include controlling theaspect ratio of the underframe 130 during growth, directionaldeposition, electro-deposition, electro-less deposition at the bottomlayer to isolate the trunk, sputter and light etch of a masking layer toopen the underframe 130 to active layer 150 growth/deposition,pre-coupling layer isolation (i.e. mask seed locations) prior to growthof the underframe 130, modifying growth parameters of the underframe 130to achieve an advantageous aspect ratio (such as a tree like structure),or performing a deposition and directional etch back to free theunder-frame 130 from coverage by active layer 150.

FIGS. 2A-2E illustrate various examples of individual nanotubes,nanofibers, nanowires and aerogel in an array. The array is optionally avertically aligned array. For clarity, the individual nanotubes,nanofibers, nanowires and aerogel are shown without the overlayingactive layer 150 etc. that is included on these elements to form EnergyStorage System 190, as illustrated in FIGS. 1A-1C. As used herein, theterm underframe is used to refer to a single structural element (e.g., asignal support filament including a nanotube, nanofiber, nanowire, oraerogel) and also to an array thereof. In some embodiments, underframe130 includes a mixture of nanotubes, nanowires and/or aerogel.

FIG. 2A illustrates an underframe 130 of vertically aligned arrays ofnanotubes or nanowires. In various embodiments, the diameter 210 of anindividual nanotube, nanofiber, or nanowire is less than 10 nm, between10 nm and 50 nm, between 20 nm and 80 nm, between 40 nm and 120 nm,between 80 mn and 300 nm, between 120 nm and 450 nm, between 255 and 710nm, between 380 nm and 1050 nm, and greater the 900 nm, or anycombination thereof. The diameter 210 can vary along the length (height)of the an individual nanotube, nanofiber, or nanowire. Note that thediameters of the individual nanotubes, nanofibers, or nanowires need notbe the same for all elements of the vertically aligned array. Thevariation in diameters can be up to 0.1%, 0.25%, 2%, 5%, 10%, 25%, orpossibly greater. In various embodiments, the underframe height 290 ofthe array is an average height and is about 1 micron to 5 microns, 2microns to 10 microns, 4 microns to 20 microns, 7 microns to 31 microns,17 microns to 57 microns, 31 microns to 123 microns, 43 microns to 253microns, 79 microns to 623 microns, 258 microns to 1289 microns,possibly larger, or any combination thereof. This height may vary as thearray of nanotubes, nanofibers, or nanowires tilts or bends. Heightvariation of the individual nanotubes, nanofibers, or nanowires may alsobe present.

FIG. 2B illustrates an underframe 130 of vertically aligned arrays ofnanotubes, nanofibers, or nanowires, with diameter variation along thelength of the nanotube, nanofibers, or nanowire. In various embodiments,the diameter 225 is less than 10 nm, between 10 nm and 50 nm, between 20nm and 80 nm, between 40 nm and 120 nm, between 80 mn and 300 nm,between 120 nm and 450 nm, between 255 and 710 nm, between 380 nm and1050 nm, and greater the 900 nm, or any combination thereof. Thediameter 225 can vary along the length (height) of the individualnanotube, nanofiber, or nanowire. Note that the diameters of theindividual nanotubes, nanofibers, or nanowires need not be the same forall elements of the vertically aligned array. The variation in diameterscan be up to 0.1%, 0.25%, 2%, 5%, 10%, 25%, or possibly greater.Additionally, by way of example, the diameter 220 can vary as differentcross-sectional shapes, such as a oval, tear drop, rectangle, diamond,or trapezoid. Other cross sectional shapes are possible. In someembodiments the diameter 220 varies as a result of a stacked-cupstructure of individual nanotubes, nanofibers, or nanowires. Thisstructure is discussed further elsewhere herein.

FIG. 2C illustrates an under-frame 130 of vertically aligned arrays ofnanofibers, with ‘graphitic’ edges exposed. This occurs in, for example,the stacked-cup structure of some carbon nanofibers. In variousembodiments, the diameter 230 is less than 10 nm, between 10 nm and 50nm, between 20 nm and 80 nm, between 40 nm and 120 nm, between 80 mn and300 nm, between 120 nm and 450 nm, between 255 and 710 nm, between 380nm and 1050 nm, greater the 900 nm, or any combination thereof. Thediameter 230 can vary along the length (height) of an individualnanotube, nanofiber, or nanowire. Note that the diameters of theindividual nanotube, nanofiber, or nanowire need not be the same for allelements of the vertically aligned array. The variation in diameters 230can be up to 0.1%, 0.25%, 2%, 5%, 10%, 25%, or possibly greater.

FIG. 2D illustrates an under-frame 130 of vertically aligned arrays ofnanotubes, nanofibers, or nanowires including branches. In variousembodiments, the diameter 240 and underframe height 290 includecharacteristics and ranges similar to those discussed above with respectto FIGS. 2A-2C (e.g., diameter 210, diameter 225, and diameter 230).

FIG. 2E illustrates an under-frame 130 of template formed aerogel. Theaerogel can be a continuous layer or in an array as illustrated. In someembodiments, the aerogel is formed without the use of a template. Insome embodiments the aerogel is mixed with the nanotube, nanofiber, ornanowire structures illustrated in FIGS. 2A-2D. In these embodiments theaerogel can be disposed in an array between the individual nanotubes,nanofibers, or nanowires, or may be deposited on the an individualnanotubes, nanofibers, or nanowires.

In various embodiments, the template aerogel diameter 250 is less than10 nm, between 10 nm and 50 nm, between 20 nm and 80 nm, between 40 nmand 120 nm, between 80 mn and 300 nm, between 120 nm and 450 nm, between255 and 710 nm, between 380 nm and 1050 nm, 510 nm and 2300 nm, 1550 nmand 4700 nm, 3380 nm and 7450 nm, 6680 nm and 15500 nm, 9870 nm and23500 nm, and greater the 50000 nm. The template aerogel diameter 250can vary along the length (height) of the aerogel and/or between membersof the array. The variation in diameters can be up to 0.1%, 0.25%, 2%,5%, 10%, 25%, or possibly greater.

FIG. 3 illustrates further details of a cross section of a portion,illustrated in FIG. 1C, of the energy storage system 190, according tovarious embodiments of the invention. These embodiments include activematerial catalyzers 310 (AMC). Active material catalyzers 310 are anexample of surface effect dominant sites but optionally or alternativelyserve to catalyze electrical chemical reactions. Surface effect dominantsites include surfaces of a nanoparticle configured to adsorb chargecarriers in a faradaic interaction, e.g., to undergo redox reactionswith charge carriers. They are referred to as “surface effect dominant”because optionally, for these nanoparticles, the faradaic interactionbetween the charge carriers and the nanoparticle surfaces dominate bulkfaradaic interactions. Thus, the charge carriers may be more likely toreact at the surface relative to the bulk of the nanoparticles. Forexample, a lithium ion could more likely adsorb onto the surface of thenanoparticle rather than being absorbed or plate into the bulk of thenanoparticle. These nanoparticles are sometimes referred to as surfaceredox particles. The faradaic interaction results in a pseudo capacitorthat can store a significant amount of loosely bound charge and thusprovide a significant power density to an energy storage device. Inpseudo capacitance an electron is exchanged (e.g., donated). In thiscase between the charge carrier to the nanoparticle. While somepotentials would result in some intercalation of charge carrier into thenanoparticle, this does not necessarily constitute the bulk of theinteraction at Surface Effect Dominant Sites and can degrade some typesof nanoparticles. A faradaic interaction is an interaction in which acharge is transferred (e.g., donated) as a result of an electrochemicalinteraction. AMCs 310 are not surface effect dominant sites in someembodiments.

However, optionally active material catalyzers 310 are typically morethan just surface effect dominant sites. In some embodiments, activematerial catalyzers 310 are configured to catalyze electro-chemicalreactions. For example, in some embodiments active material catalyzers310 are configured to release oxygen from a compound including lithiumand oxygen. In some embodiments the catalyzers 310 are configured tocatalyze Li⁺+½O₂+e⁻←→½Li₂O₂ and/or Li⁺+¼O₂+e⁻←→½Li₂O, or any otherreactions known in the art of lithium based batteries. The interactionsthat occur at active material catalyzers 310 may be dependent on thepotentials applied.

Active material catalyzers 310 can be implemented as nanoparticlesand/or thin films. Active materials catalyzers 310 are generallycomprised of materials such as gold, platinum, MnO_(x), CuFe,beta-MnO₂/Pt, Pd, Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄, CoFe₂O₄,TiN, TiC, TiO₂, and/or any combination thereof.

As nanoparticles, active material catalyzers 310 can have averagediameters of up to 1 nm, 3 nm, 5 nm, 8 nm, 13 nm, 17 nm, 23 nm, 29 nm,37 nm, 43 nm, 53 nm, 61 nm, 67 nm, 79 nm, 97 nm, 115 nm, possiblylarger, and/or any combination thereof. Note that the nanoparticles canhave multiple sizes, therefore implying a distribution of particle size.This distribution is not necessarily a normal distribution, e.g., thedistribution may be bimodal. These nanoparticles can be found as part ofthe underframe 130, underlayer 152, active layer 150, and/or overlayer154.

Thin film AMCs 310 have an average thickness range from about 1 nm to 5nm, 3 nm to 7 nm, 5 nm to 12 nm, 10 nm to 17 nm, 13 nm to 25 nm, 20 nmto 47 nm, 29 nm to 53 nm, 37 nm to 71 nm, 57 nm to 101 nm, possiblylarger, or any combination thereof. Thin film AMCs 310 can be part ofthe underlayer 152 and/or the overlayer 154. The active layer 150 isoptionally comprised of Li₂O₂, Li₂O, lithiated TiS₂, LiOH*H₂O, LiOH,(LiMO₂, M=Mn, Ni, Co), LiFePO₄, TiO₂, lithiated TiO₂, and/or anycombination thereof. In various embodiments, the thickness of the activelayer is from 1-10 nm, 5-50 nm, 15-75 nm, 25-100 nm, 50-200 nm, 80-350nm, 120-600 nm, 175-950 nm, 250-1500 nm, 425-2500 nm, 725-4000 nm,possibly larger, or any combination thereof.

Note that while the distribution of AMCs 310 within each layer of FIG. 3are shown to be relatively uniform, in alternative embodiments the AMCs310 are concentrated at one or the other edge of any of the layers,and/or may be concentrated at a boundary between any two of the layersillustrated. For example, in some embodiments AMCs 310 are concentratedaround the boundary between Overlayer 154 and Active Layer 150, and/orat the boundary between Active Layer 150 and Underlayer 152. Suchconcentrations can be achieved, for example, by depositing the AMCsbetween steps of generating any two of the illustrated layers and/orunderframe 130. AMCs 310 may be disposed as a gradient within any of thelayers illustrated. In some embodiments, AMCs 310 include oxygenadsorbing materials.

FIG. 4A illustrates a cross section of several elements of an energystorage electrode with stacked-cup nanofibers, according to variousembodiments of the invention. Specifically, stacked-cup nanofibers haveexposed graphitic edges and planes that act as graphene sheets. Thesegraphene sheets wrap around a central ‘core’. These sheets layer on topof each other, creating increased surface area relative to standardnanotubes (which typically have a smooth surface). Additionally, thestacked sheets create channels to the central core of the cuppednanofiber 410. These stacked-cup nanofibers can be in a verticallyaligned array as illustrated in FIG. 2C or separated from the surface onwhich they were grown and attached as a mesh to a new substrate using abinder. Further examples of the stacked-cup structure are illustrated inFIGS. 3A-3C and 4 of U.S. patent application Ser. No. 13/935,334 filedJul. 3, 2013.

FIG. 4B illustrates a detailed cross section of several elements (“cupedges”) of a stacked-cup nanofiber with exposed ‘graphitic’ edges,according to various embodiments of the invention. In particular, theexposed graphitic edge sheets allow for incursion of particulate activematerial catalyzer 310 including the materials and characteristicsdiscussed elsewhere herein, between the graphitic edges. See region “A”in FIG. 4B.

Optionally, an element of energy storage system 190 can be created, withall the attributes as listed and shown in FIG. 3, on each exposedgraphite edge of stacked-cup nanofiber. See region “B” in FIG. 4B. Anadditional attribute of the stacked-cup nanofiber structure is theexistence of a gas storage channel for gas sequestration. See region “C”in FIG. 4B. This channel optionally provides a path for gasses to reacha hollow central core within the nanofiber. Such gasses can include O₂,CO₂, CO, N₂, NO₂, NO, H₂, etc. By way of example, in some embodiments,an oxygen absorber (not shown) such as strontium cobaltite, is includedin the channel 440 between the exposed (graphene like) stacked-cup edgesto capture excess oxygen. Other materials can optionally be used tocapture and release other gases. Absorbers of the above gasses may alsobe included within the hollow central core 450 of a stacked-cupnanofiber or an unzipped nanotube.

The various features illustrated in regions “A,” “B” and “C” of FIG. 4may be including in stacked-cup nanofibers in any combination. Forexample, one embodiment includes the particulate active materialcatalyzer 310 illustrated in region “A,” the active layer 150 includedin region “B,” and room for oxygen sequestration illustrated in region“C.” These are optionally included within the same channel 440.

FIG. 5A illustrates a cross section of several elements of an energystorage electrode including a template formed aerogel, according tovarious embodiments of the invention. Specifically, the aerogel has anaverage density that ranges from about 0.008 g/cm³ to 0.3 g/cm³, asurface area that ranges from about 200 m²/g to 2000 m²/g, a pore volumethat ranges from about 0.5 cm³/g to 25 cm³/g, and an average porediameter that ranges from about 2 nm to 50 nm.

FIG. 5B illustrates a cross section of an aerogel 510, according tovarious embodiments of the invention. In some embodiments, exposedaerogel pores 520 and resulting large surface area allow for incursionof active material catalyzer 310 within the aerogel. An example isillustrated in region “A” of FIG. 5B.

In some embodiments, an energy storage system 190 (with or withoutactive material catalyzer 310) can be created on surfaces of theaerogel. These embodiments of energy storage system 190 can include anyor all the attributes and characteristics discussed elsewhere herein. Anexample of energy storage system 190 is illustrated in region “A” ofFIG. 5B. This example can be included on any or all of the availablesurfaces of the aerogel 510. The surfaces and boundaries between thepores function as the underframe 130. The active material catalyzer 310shown in region “A” and the energy storage system 190 shown in region“B” are optionally found together, e.g., the active material catalyzer310 can be included in the energy storage system 190 as discussedelsewhere herein.

An additional attribute of the aerogel is the presence of a gas storagechannels for gas sequestration. Such gases can be O₂, CO₂, CO, N₂, NO₂,NO, H2, etc. These channels exist within the aerogel pores 520 of theaerogel. By way of example, an oxygen absorber (such as strontiumcobaltite), can optionally be placed in the channel to capture excessoxygen. Other materials can optionally be used to capture and releaseother gases. The embodiments described in relation to FIG. 5B may beapplied to a continuous aerogel (not shown). In these embodiments,nanofibers are grown on an aerogel substrate (which in turn is on a moresolid substrate 110). The aerogel substrate may include an oxygenabsorber and the nanofibers may support the energy storage system 190 asdiscussed herein.

FIG. 6 illustrates a cross section of a prior art rechargeable battery(e.g., a secondary battery/cell 600). This battery includes a cathode610, an anode 620, a separator 630 and an electrolyte 640. The variousembodiments illustrated in FIGS. 1-5 and discussed herein may be appliedto either the cathode 610 or anode 620. The secondary battery/cell 600may take many geometric forms and shapes as would be apparent to one ofordinary skill in the art. The cathode 610 may be open to the atmosphereor sealed from the atmosphere.

FIG. 7 illustrates a method for fabricating an electrode including anenergy storage system 190 including an underframe 130. The first step701 is to receive a substrate 110. Substrate 110 is optionally graphitecoated aluminum, graphite, Ni, Ag, Fe, Mg, Pb, W, AI, Hf, Mo, Pd, Ta,Au, In, Nb, Ti, Zr, Cu, Li, Ni, V, Zn, C, carbides of previously notedmaterials, silicides of previously noted materials, oxides of previouslynoted materials, nitrides of previously noted materials, an oxygenpermeable membrane, or any combination thereof. Note that the substrate110 can include one material, or a combination of several materials. Thesubstrate 110 can be of other materials, depending on the desiredapplication. For instance, aerogel, stainless steel or graphite can beused for a substrate. Those skilled in the art of battery design canfurther specify other materials, depending on the desired application.In some embodiments substrate 110 is flexible and configured to becoiled.

An optional second step 703 is to clean the substrate 110. The purposeof cleaning 703 the substrate 110 is to prepare the substrate 110 forthe subsequent depositions and growth of materials in later processsteps. It is meant to remove any undesired organics, oxides, and othercontaminates present on the substrate 110. The methods to clean thesubstrate 110 can range from physical (using an abrasive, for instance,to remove a thin layer of material that has been exposed tocontaminants), to chemical (using a solvent, such as acetone,iso-propanol, TCE, or methanol) and/or chemical etch (citric acidsoak/rinse, which dissolves part of the actual substrate, in the case ofcopper), or any combination of physical and chemical methods toappropriately prepare the surface 110 for subsequent process steps.

A third step 705 is an optional seed layer deposition. Seed layerdeposition 705 is the process step where the base layer, or seed layer115, for underframe 130 growth is created. This process step can beimplemented through a gas phase (physical or chemical)deposition/growth, a liquid phase deposition/growth, or a solid phasedeposition/growth, or any combination thereof.

Physical gas phase deposition techniques (where the material to bedeposited is transported from the source to the substrate in the gasphase) can include: thermal evaporation, electron beam evaporation, DCsputtering, DC magnetron sputtering, RF sputtering, pulsed laserdeposition, cathode arc deposition, and/or the like. It is also possibleto use reactive physical vapor deposition, a method by which a‘contaminate gas’ is injected into the chamber during the growthprocess, thereby incorporating itself into the layer as it grows.

Chemical gas phase deposition techniques (where chemical precursors aretransported to the surface in the gas phase, and then subsequentlyundergo a chemical reaction at the surface) can include Low PressureChemical Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition,Atmospheric Pressure Chemical Vapor Deposition, Metal-Organic ChemicalVapor Deposition, Hot-wire Chemical Vapor Deposition, Very HighFrequency Plasma Enhanced Chemical Vapor Deposition, Microwave PlasmaEnhanced Chemical Vapor Deposition, and/or the like.

Liquid phase deposition techniques to create the seed layer 115 caninclude plating, electroplating, or chemical solution deposition, etc.Solid phase deposition techniques can include focused ion beamdeposition. Another possibility for deposition is a solution thatcontains a liquid and a suspension of appropriate sized particles thatare sprayed onto the current collector, and then the substrate issubsequently ‘cured’ such that the carrier solution is removed, leavingthe particles intact on the surface of the substrate.

Any combination of the above process steps can be used to create anappropriate seed layer 115 for creating the initiation sites for theunderframe 130 growth.

A forth step 715 in the process is the creation of the initiation sites,defined as the location where the underframe 130 starts growth on theseed layer 115. This step is dependent on methods chosen to create theseed layer 115. For instance, the initiation sites separation distancecan be determined by the thickness and materials chosen for seed layerdeposition 705. For instance, a seed layer of 3000 angstroms nickel/300angstroms chrome will produce a certain number of initiation sites persquare centimeter. If the thickness of the nickel is reduced to 2000angstroms, the number of initiation sites per square centimeter will bedifferent than that for a thickness of 3000 angstroms nickel. If anothermaterial is chosen, such as iron to replace nickel, the resultantinitiation sites per square centimeter will also be different. Step 715is optionally part of step 705.

A solid phase deposition technique can allow for control of theinitiation sites per square centimeter. This can be a focused ion beamdeposition, where the initiation sites/cm² are directly controlled bythe by where the focused ion beam deposits it material, or anano-particle suspension, where the initiation sites/cm² is controlledby the number of nano-particles contained in a given suspension volume.The number of initiation sites can also be controlled by the size of thefocused ion beam deposition site, or the size of the nano-particles insolution, etc.

The initiation sites are typically created when a reactor in which theelectrode is produced reaches the appropriate reaction temperature withthe appropriate feedstock gases flowing, and the feedstock gas begins tocatalyze with the seed layer 115. The initiation sites have thus beencreated, and the underframe 130 growth has commenced.

A fifth step 720 is to grow the underframe 130. There are a number ofgrowth processes available to grow the underframe 130. For example,chemical Vapor Deposition, Thermal Chemical Vapor Deposition,Vapor-Liquid-Solid growth (a type of CVD), and Plasma Enhanced ChemicalVapor Deposition, are processes by which Nano-Tube (NT), Nano-Fiber(NF), and Nano-Wire (NW) growth has been achieved. Those skilled in theart of filament growth will recognize that there are other growthmethods available.

Examples of feedstock gases that can be used to grow NT/NF are carbonmonoxide, methane, ethane, ethylene, acetylene, and/or the like. It isalso possible to use other hydrocarbons or inorganic compounds for thegrowth process.

Of interest is the Plasma Enhanced Chemical Vapor Deposition (CVD)method, due to the fact that the growth of the support filament 110aligns with the electric field of the plasma, thus allowing for theproduction of vertically aligned underframe 130. Thermal CVD, undercertain process conditions, can also produce vertically alignedunderframe 130 units. Further, Water-Assisted CVD makes possible veryhigh aspect ratio vertically aligned underframe 130 (length vs. diameterroughly equal to 1,000,000), allowing for very tall underframe 130.

It has also been demonstrated that appropriately modified bacteria andviruses have grown to nanowire and nanofiber structures. Such techniquesare optionally used to create underframe 130.

It is also possible to use several of the techniques together at once,with the appropriate choice of material. For instance, bacteria/virusescan be used to grow the NT/NF/NW in the presence of an applied electricfield, producing vertically aligned support filaments. Another method ofunderframe 130 growth is to apply an electric and/or magnetic fieldduring VLS growth to control the trajectory of the growing NT/NF/NW,this controlling the three dimensional shape of the underframe 130.Another technique is to begin growth of the NT/NF/NW underframe 130 withthe reactor operating in PECVD mode; after a specified time, the reactorcan be converted to Thermal CVD mode; and then again, after a specifiedtime, the reactor is converted back to PECVD mode. Those skilled in theart of NT/NF/NW growth can appreciate that there are other possiblecombinations that allow for appropriate growth control of the supportfilament 110.

The underframe height 290 of the underframe 130 is generally determinedby the duration of the growth process. The temperature of the reactor,the feedstock gases used, and the combination and strength of appliedelectric and magnetic fields (or the absence thereof) can influence thespeed and amount of filament growth.

The diameter 210 of the underframe 130 is generally determined by thethickness of the seed layer 115, or the size of the nano-particlescontained in suspension, if a nano-particle suspension method is chosento create the seed layer 115, or the size of the ion beam, if focusedion beam deposition is chosen to create the seed layer 115. Thetemperature of the reactor, the feedstock gases used, and thecombination and strength of applied electric and magnetic fields (or theabsence thereof) can influence diameter of the underframe 130 as well.This also applies to diameters 225, 230, and 240.

During the growth step 720 of underframe 130, it is possible toimplement a sub-step 720 a, where the diameter and number of branchescan be affected. This can be accomplished by changing temperature of thereactor, the feedstock gases used and their relative compositions andflow rates, direction and strength of applied electric and magneticfields (or the absence thereof). The duration of the change implicitlydetermines the diameters 210 225, 230 and 240), as well as the amount ofbranching, as shown in FIG. 2D.

During the growth step 720 of underframe 130, it is possible toimplement a sub-step 720 b, where the diameter and number of branchescan be affected. This can be accomplished by changing temperature of thereactor, the feedstock gases used and their relative compositions andflow rates, direction and strength of applied electric and magneticfields (or the absence thereof). The duration of the change implicitlydetermines the NT/NF diameter 210 (as well as the other diameters 225,230, and 240), as well as the amount of branching, as shown in FIG. 2D.

The diameter, thickness, height, and branches of underframe 130 arelargely controlled by the changes in the aforementioned parameters; thiscan be done on a somewhat continuous basis by changing the inputparameters for growth, creating the equivalent sub-steps 720 c, 720 d,etc., until it is decided to terminate growth.

If an aerogel is desired, the growth process requires the preparationand setting of a gel on the optional seed layer 115. In someembodiments, when ageing of the gel is complete, the gel is exchangedinto 200 proof ethanol (or acetone) about four times over the course ofa week. After one week, supercritically dry the gel. Thus, an aerogel isproduced. Note that the template size can be defined by mechanicallymasking the locations where the aerogel is desired. Alternatively, thesize of the aerogel template can be defined by photolithography. Thethickness of the aerogel template can be defined by the thickness of theoriginally deposited gel on the seed layer 115/substrate 110.

The eighth process step 730 is deposit/grow the energy storage system190. The growth/deposition of the energy storage system 190 can beimplemented through a gas phase (physical or chemical)deposition/growth, a liquid phase deposition/growth, or a solid phasedeposition/growth, or any combination thereof.

Physical gas phase deposition techniques (where the material to bedeposited is transported from the source to the substrate in the gasphase) can include: thermal evaporation, electron beam evaporation, DCsputtering, DC magnetron sputtering, RF sputtering, pulsed laserdeposition, cathode arc deposition, and/or the like. It is also possibleto use reactive physical vapor deposition, a method by which a‘contaminate gas’ is injected into the chamber during the growthprocess, thereby incorporating itself into the layer as it grows.

Chemical gas phase deposition techniques (where chemical precursors aretransported to the surface in the gas phase, and then subsequentlyundergo a chemical reaction at the surface) can include Low PressureChemical Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition,Atmospheric Pressure Chemical Vapor Deposition, Metal-Organic ChemicalVapor Deposition, Hot-wire Chemical Vapor Deposition, Very HighFrequency Plasma Enhanced Chemical Vapor Deposition, Microwave PlasmaEnhanced Chemical Vapor Deposition, and/or the like.

Note that in any deposition stage more than one material can bedeposited at a time. For instance, two (or more) different types ofmetal can be deposited/grown at the same time, such as tin (Sn) and gold(Au); two (or more) different types of semiconductor can bedeposited/grown, such as silicon (Si) and germanium (Ge); two (or more)different types of oxide may be grown/deposited, such as lithium ironphosphate (LiFePO₄) and lithium nickel cobalt manganese (Li(NiCoMn)O₂).Additionally, it is possible to mix material types, such as a metal anda semiconductor, or a semiconductor and an oxide, or a metal and anoxide, or a metal, semiconductor, and oxide. Examples include silicon(Si) and lithium (Li) co-depositions, silicon (Si) and LiO₂ (or SiO₂)co-depositions, and silicon (Si), lithium (Li), and LiO₂ (or SiO₂)co-depositions. It may be desirable to co-deposit insulating material aswell, such as silicon dioxide (SiO₂), or silicon nitride (Si₃N₄).Additionally, it may be desirable to co-deposit carbon (C) as well. Notethat depositing of active materials (such as Li₂O₂, Li₂O, lithiatedTiS₂, LiOH*H₂O, LiOH, (LiMO₂, M=Mn, Ni, Co), LiFePO₄, lithiated TiO₂,and/or any combination thereof) can optionally be performedsimultaneously with catalyst materials (such as gold, platinum, MnO_(x),CuFe, beta-MnO₂/Pt, Pd, Ru, MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄,CoFe₂O₄, TiN, TiC, TiO₂, or any combination thereof).

The energy storage system 190 is optionally created by a liquid phaseprocess, such as electro-less deposition or electro-plating. It is alsopossible to create the energy storage system 190 by coating theunderframes 130 with a solution containing active materials (such asLi₂O₂, Li₂O, lithiated TiS₂, LiOH*H₂O, LiOH, (LiMO₂, M=Mn, Ni, Co),LiFePO₄, lithiated TiO₂, and/or any combination thereof) and/or catalystmaterials (such as gold, platinum, MnO_(x), CuFe, beta-MnO₂/Pt, Pd, Ru,MoN/NGS, Li₅FeO₄, Li₂MnO₃*LiFeO₂, FeO₄, CoFe₂O₄, TiN, TiC, TiO₂, or anycombination thereof), suspended in a binder solvent matrix. Afterappropriate processing, the solvent is driven out of the matrix, leavingonly the binder and active/and/or catalyst material, thus creating anelectrode including underframe 130 and energy storage system 190. Thistechnique can be applied to both an anode and cathode, with appropriatechoice of materials.

In some embodiments, the reactivity of the energy storage system 190 iscontrolled by appropriately choosing the deposition and growthtechnique. For instance, it is possible include catalyst materialsduring the deposition process of the active layer 150.

In some embodiments, the deposited/grown energy storage system isencapsulated. This encapsulation could be gel electrolyes, such asP(VDF-HFP)-based polymer electrolytes, poly acrylic acid, andpolyfluorene-based conducting polymers, incorporating a carbon-oxygenfunctional group (carbonyl).

At step 740 the electrode fabrication may be complete. The electrode isoptionally included within a battery.

As used herein, the term “nanofibers” is meant to include nano-ribbon,nano-filaments, unzipped nanotubes, nanowires and/or nanotubes.

Several embodiments are specifically illustrated and/or describedherein. However, it will be appreciated that modifications andvariations are covered by the above teachings and within the scope ofthe appended claims without departing from the spirit and intended scopethereof. For example, energy storage systems 190 are optionally formedon both sides of Substrate 110. The teachings disclosed herein may beapplied to both batteries and hybrid battery/capacitors. In someembodiments material catalyzer 310 migrates from one layer to anotherduring operation. In some embodiments, the particles discussed hereinare multi-layered or hollow particles.

The embodiments discussed herein are illustrative of the presentinvention. As these embodiments of the present invention are describedwith reference to illustrations, various modifications or adaptations ofthe methods and/or specific structures described may become apparent tothose skilled in the art. All such modifications, adaptations, orvariations that rely upon the teachings of the present invention, andthrough which these teachings have advanced the art, are considered tobe within the spirit and scope of the present invention. Hence, thesedescriptions and drawings should not be considered in a limiting sense,as it is understood that the present invention is in no way limited toonly the embodiments illustrated.

What is claimed is:
 1. A battery comprising: a cathode; an electrolyte;and an anode, the anode including a substrate, a plurality of supportstructures attached to the substrate, an active layer disposed on thesupport structures, and an over-layer disposed between the active layerand the electrolyte, with the over-layer configured to act as a barrierbetween the electrolyte and the active layer.
 2. The battery of claim 1,wherein the over-layer has a thickness between 1 and 101 nm.
 3. Thebattery of claim 1, wherein the over-layer includes nanoparticles. 4.The battery of claim 3, wherein the nanoparticles have an averagediameter between 1 and 115 nm.
 5. The battery of claim 1, wherein theover-layer is configured to encapsulate the active layer.
 6. The batteryof claim 1, wherein the over-layer includes titanium.
 7. The battery ofclaim 1, wherein the support structures are attached to the substrateusing a binder.
 8. The method of claim 1, wherein the active layerincludes silicon.